It is known to lay dust in coal mines by spraying with aqueous systems containing chemical additives to improve working conditions and reduce the toxicological risks and explosion hazards. Most commonly used chemicals for for this purpose are hydroscopic salt mixtures. It has been proposed that the dust may be layed by spraying the dusty areas with water containing surfactants. United Kingdom Pat. No. 677279 describes the use of aqueous systems containing alkyl benzene sulphonates in which the alkyl group contains from 10 to 12 carbon atoms while U.S. Pat. No. 4,067,818 teaches those in which the alkyl group contains 9 carbon atoms.
U.S. Pat. No. 3,900,611 utilizes the combination of an amphoteric surfactant with an anionic surfactant (sulfosuccinate) in an aqueous solution of a polymer such as polyacrylamide.
Sulfosuccinates are taught to have activity in coal dust abatement (see J. O. Glanville et al, Fuel, Vol. 58, pp 819-22 (1976) and P. L. Walker Jr., et al I&I Ch, 2389-2393 October, 1952) and the former citation compares its activity with the activity of a non-ionic surfactant, polyethoxylated octyl phenol.
The wetting power is a measure of the extent to which the dust-laying composition spreads over the surface of the dusty area, (i.e., the coal) thus increasing the extent to which the dust is laid. The greater the wetting power of the composition, the greater the dust laying effect for the same amount of composition which is of course economically important. Thus, by using surfactants with a greater wetting effect it is possible to achieve the same power from a composition containing less surfactant which is also economically and environmentally important.